[SOLVED] Shairport-sync on Raspberry PI zero w: service visible but can't connect

[BurgerKing64]

I installed the version from GitHub (3.3.8rc3-OpenSSL-Avahi-ALSA-soxr-sysconfdir:/etc) on RaspiOS Buster running on a RPI zero w. The problem is that I can see the service from my ios devices, but can't connect. Following the answers to similar problems I tried to check with avahi-browse, but everything seems ok:

pi@raspberrypi:~/shairport-sync $ avahi-browse -a
+  wlan0 IPv6 871D4655FAF3@Rotel                            AirTunes Remote Audio local
+  wlan0 IPv4 871D4655FAF3@Rotel                            AirTunes Remote Audio local

On ios side I installed Discovery: under the dacp section I can see the service, but when I try to open it the program gives an error. Shairport appears to be up and running:

* shairport-sync.service - Shairport Sync - AirPlay Audio Receiver
   Loaded: loaded (/lib/systemd/system/shairport-sync.service; enabled; vendor preset: enabled)
   Active: active (running) since Mon 2021-03-22 15:30:25 GMT; 5min ago
 Main PID: 1052 (shairport-sync)
    Tasks: 4 (limit: 877)
   CGroup: /system.slice/shairport-sync.service
           `-1052 /usr/local/bin/shairport-sync

mar 22 15:30:25 raspberrypi shairport-sync[1052]:          0.000112999 "shairport.c:1917" loudness is 0.
mar 22 15:30:25 raspberrypi shairport-sync[1052]:          0.000127998 "shairport.c:1918" loudness reference level is -20.000000
mar 22 15:30:25 raspberrypi shairport-sync[1052]:          0.016247747 "audio_alsa.c:1943" keep_dac_busy is now "no"
mar 22 15:30:25 raspberrypi shairport-sync[1052]:          0.083180707 "mdns_avahi.c:209" avahi: service '871D4655FAF3@Rotel' group is not yet committed.
mar 22 15:30:25 raspberrypi shairport-sync[1052]:          0.011734818 "mdns_avahi.c:251" avahi: request to add "_raop._tcp" service without metadata
mar 22 15:30:25 raspberrypi shairport-sync[1052]:          0.016235747 "mdns_avahi.c:375" avahi_dacp_monitor_start Avahi DACP monitor successfully started
mar 22 15:30:25 raspberrypi shairport-sync[1052]:          0.001087983 "mdns_avahi.c:213" avahi: service '871D4655FAF3@Rotel' group is registering.
mar 22 15:30:26 raspberrypi shairport-sync[1052]:          0.857376672 "mdns_avahi.c:180" avahi: service '871D4655FAF3@Rotel' successfully added.
mar 22 15:30:27 raspberrypi shairport-sync[1052]:          0.532454723 "shairport.c:194" soxr_delay_index: 15.
mar 22 15:30:27 raspberrypi shairport-sync[1052]:          0.004673927 "shairport.c:201" "soxr" interpolation has been chosen.

Any idea on how to debug this? Thanks in advance for the support.

[mikebrady]

Thanks for the post. Shairport Sync looks like it is working. So, what could it be that isn't working?

Could I suggest you take a look through the TROUBLESHOOTING.md page? Failing that, there is a [long] issue report at #727 that might help.

[BurgerKing64]

Thank you for the quick answer. I checked thoroughfully the troubleshoowing page, but i didn't find anything that could match my situation:

• Both the iphone and the Raspberry are connected to the same network
• No VPNs are active
• The power_save is off on the wifi connection (i disabled it and checked with iwconfig)
• Ufw is not installed on the pi; there's a basic firewall running on the modem, but disabling it doesn't change the situation
• No error messages related to wifi appear in the syslog, unlike to report #727. Anyway an old Apple tv connected on the same nework works without issue.
• shairport-sync seems to start properly at boot.

To be sure I tried to remove the program as you suggested in your guide and to reinstall it from the scratch, but the situation didn't change. I only noticed two new facts:

1. Shairport seems to disappear from the services seen by iphone after a while. The only way to have it back is to stop the service, than restart it. I checked with Discovery and it's the whole _raop_tcp that disappears (maybe this is normal since Shairport is the only Airport service present).
2. When the service is visible i succeded in getting a log from Discovery. This is what I found:

   
   Remote Audio Output Protocol (AirTunes)

raspberrypi.local:5000 192.168.1.137:5000 fe80::656a:7ed0:5683:ce9c%en0:5000

am = ShairportSync ch = 2 cn = 0,1 da = true ek = 1 et = 0,1 fv = 76400.10 md = 0,1,2 pw = false sf = 0x4 sr = 44100 ss = 16 sv = false tp = TCP,UDP txtvers = 1 vn = 65537 vs = 105.1

3. Also when the service disappears, the status read from the Pi reports Shairport running, as in the log I copied in the first post.
Could you suggest any other way to debug the issue? I know that it's probably some stupid setting on my setup, but I've run out of ideas on what to check...). 

Thanks again for the support and for your work

[BurgerKing64]

Looking at another issue where the cause was the modem I had the idea to move both the Raspberry and the iphone to another network made with a cheap DLink access point: everything worked fine. I still wonder what's wrong with my main modem, which otherwise works well: probably, since it is a VDSL one provided by the telephone company for FTTH and lacking many fine settings, probably there is some parameter set that is not visible to me.
I think that the issue can be considered solved. Many thanks for the help and, of course, for the software!

[mistakenideas]

@BurgerKing64 I know some VDSL routers have settings which prevent devices on the wireless network from communicating with each other which can cause problems. Could be worth checking the wireless security settings?

[BurgerKing64]

@mistakenideas Likely it is so, but unfortunately the modem is a Technicolor AG plus VDNT-S Router VDSL2 with a firmware customised by the internet provider, so all the advanced settings are not present. I can only change the modem address, enable/disable the NAT and the DHCP. Nothing about security, apart a basic firewall whose deactivation doesn't change much. Thank you for the advice anyway.

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